Suppress -Wdeprecated-copy-dtor for Skia.

Bug: None
Change-Id: I20c7f201223c07af909a5a85bdd9c004d2c5cd30
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/31563
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>

src/common/BUILD.gn

@@ -121,6 +121,9 @@ config("dawn_internal") {
     #   if (myUint64 > std::numeric_limits<size_t>::max()) {...}
     cflags += [ "-Wno-tautological-type-limit-compare" ]
 
+    # Suppressions for warnings found in Skia that should really be fixed.
+    cflags += [ "-Wno-deprecated-copy-dtor" ]
+
     if (is_win) {
       cflags += [
         # clang-cl doesn't know -pedantic, pass it explicitly to the clang driver